ALLSCHWIL, SWITZERLAND – 26 March 2015 – Actelion (SIX: ATLN) announced today that Japan’s Ministry of Health, Labor and Welfare granted marketing approval for Opsumit® (macitentan) for the treatment of pulmonary arterial hypertension (PAH).

The approval was based on data from a local study conducted in Japan and the landmark global Phase III SERAPHIN study. In both studies, improvements in pulmonary vascular resistance, 6MWD, and WHO function class were observed. In the SERAPHIN study, treatment with macitentan 10 mg per day resulted in a 45% risk reduction (p <0.0001) of the composite morbidity-mortality endpoint when compared to placebo.

Satoshi Tanaka, Dr. med Sci. President of Actelion Japan commented: “Opsumit represents a major step forward for the management of PAH as the first and only approved PAH treatment with proven long-term outcome efficacy. We are delighted to be able to add Opsumit to our PAH portfolio alongside epoprostenol ‘ACT’ and Tracleer as another crucial element in successful PAH management for physicians across Japan.”

Jean-Paul Clozel, M.D. and Chief Executive Officer of Actelion commented: “This is a great achievement for Actelion Japan. This approval is based on the SERAPHIN data and the local Japanese study performed by Actelion Japan. I am very happy that the Japanese PAH patients can soon benefit from Opsumit, an innovative product discovered in our laboratories.”

The most common adverse events that were reported in the SERAPHIN study at a frequency at least 3% greater on macitentan than on placebo were nasopharyngitis, headache, anemia, bronchitis, urinary tract infection, pharyngitis and influenza.

Opsumit was approved by the US FDA in October 2013 and by the EU Commission in December 2013. Launch activities are progressing rapidly, with market introductions in the US, EU, Australia, Canada and Switzerland.

Actelion Pharmaceuticals Japan will co-promote Opsumit with Nippon Shinyaku in Japan and the companies will jointly ensure that Opsumit is made available to patients as soon as possible.